OCL 2015, 22(4) D403 c T. Bardeau et al., Published by EDP Sciences 2015 OCL DOI: 10.1051/ocl/2015004 Oilseeds & fats Crops and Lipids Available online at: www.ocl-journal.org Research Article –Dossier Open Access 12TH EURO FED LIPIDS CONGRESS: OILS, FATS AND LIPIDS: FROM LIPIDOMICS TO INDUSTRIAL INNOVATION Recovery of oils from press cakes by CO2-based technology Tiphaine Bardeau1,2,3, Raphaelle Savoire1,2,3,, Maud Cansell1,2,3 and Pascale Subra-Paternault1,2,3 1 Université de Bordeaux, CBMN, UMR 5248, 33600 Pessac, France 2 CNRS, CBMN, UMR 5248, 33600 Pessac, France 3 Bordeaux INP, CBMN, UMR 5248, 33600 Pessac, France ossier D Received 7 January 2015 – Accepted 22 January 2015 Abstract – In a context of a strong demand for vegetable oils, the development of new “green" processes is essential to provide methods that avoid the use of organic solvents, work at relatively low temperatures and preserve the quality of the final products. The supercritical fluid extraction (SFE) process meets these objectives. In this study, five meals (hemp, flax, sesame, poppy and walnut) were subjected to SFE at 45 ◦C and 250 bar in the presence of ethanol as co-solvent. Using this method, between 77 and 98% of the lipids present in the meal could be extracted. Except for poppy, 50% of the lipids present in the cake were recovered as a separate oily liquid phase. SFE was not selective toward certain types of triglycerides: the oils obtained exhibited the same fatty acid profile than the total lipid extracts from the cakes. In contrast, the composition in minor lipid components was dependent on the type of meal investigated. For example, hemp lipid extract was particularly rich in chlorophyll. Keywords: Supercritical fluid extraction / press cake / oil recovery / oil quality Résumé – Technologie à base de CO2 pour l’extraction d’huiles de tourteaux de pressage. Dans un contexte de forte demande en huiles végétales, le développement de nouveaux procédés « verts » est indispensable pour proposer des procédés évitant l’utilisation de solvants organiques, travaillant à relativement basse températures et préservant les qualités nutritionnelles et organoleptiques des produits finaux. Le procédé d’extraction par fluide supercritique (EFS) répond à ces objectifs. Dans cette étude, cinq tourteaux végétaux (chanvre, lin, sésame, pavot et noix) ont été soumis au procédé d’EFS à 45 ◦C et 250 bar en présence d’éthanol comme co-solvant. Ce procédé a permis d’extraire entre 77 et 98% des lipides présents dans les tourteaux. À l’exception du pavot, 50% des lipides présents dans les tourteaux se retrouvent sous la forme d’une phase liquide huileuse indépendante. L’EFS n’est pas sélective vis-à-vis de triglycérides particuliers. En effet, l’huile extraite a le même profil en acides gras que les lipides totaux du tourteau. Néanmoins, selon la nature du tourteau considéré, la composition en composés lipidiques mineurs est très variable. Par exemple, la quantité de chlorophylle extraite est très importante dans le cas du tourteau de chanvre. Mots clés : Extraction par fluide supercritique / tourteau de pressage / extraction d’huile / qualité de l’huile 1 Introduction (Fine, 2013). As an alternative and eco-efficient approach, su- percritical fluid extraction (SFE) can be envisaged. Oil demand is in constant increase for years due to nutri- tional and industrial issues. For nutritional aspects, recommen- The recovery of oil from oilseeds by SFE is a solid-fluid dations concerning the omega 3/omega 6 balance are respon- extraction process that uses mostly carbon dioxide as extract- ing fluid. Indeed, oil solubility in supercritical carbon dioxide sible for new developments in specialty oils and for a global / increase of the oil volume demand. In the same time, the use (scCO2) is relatively high (0.1 to 200 g oil kg CO2) depend- i.e of oil for biodiesel production is also increasing. By still con- ing on the fluid density ( . pressure and temperature) (del et al. taining 10 to 30% of oil, press cakes are valuable sources of Valle , 2012). ScCO2 is an apolar fluid so ethanol is of- oils that, by regards of environmental and human health con- ten used as a cosolvent to modify its polarity and to favor co- cerns, could be recovered by eco-efficient processes. So far, extraction of more polar compounds. SFE of oilseeds has been extensively studied on various matrices over the past decades large scale oil facilities process is based on a pressing step fol- lowed by a solvent extraction using hexane to exhaust the cake (Eggers, 1996). However, SFE applied on press cakes is more confidential and the consequences of pressing on SFE perfor- Correspondence: [email protected] mances still have to be evaluated. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. T. Bardeau et al.: OCL 2015, 22(4) D403 Table 1. Press cake compositions (different letters are for statistically different lipid content (Tukey HSD test at 95% confidence interval)). Hemp Linseed Poppy Sesame Walnut Water content∗ (% db) 7.3 (12) 8 ± 1(12) 9.2 (12) 7.6 (10) 5.4 (10) Lipid content∗ (%db) 11 ± 2c 11 ± 1a,c 12 ± 1a,c 23 ± 2b 8 ± 1a (12) (12) (12) (25) (45) Ash (%)∗∗ 15 10 15 10 10 Proteins (%wb)∗∗ 25–40 15–45 30–45 30–50 20–40 Cellulose (%wb)∗∗ 20–35 10 5–15 10 10 ∗ Values in parentheses are from supplier’s datasheet. ∗∗ Values are from supplier’s datasheet. In this work, SFE was investigated as a technique to re- oils; measured with the Rancimat method). So SFE oils were cover residual edible oils from various press cakes present- more degraded and less stable than cold pressing oils. How- ing different fatty acid profiles. Hempseed oil is a linoleic oil, ever, SFE oils contained higher amounts of carotenoids (9 μg/g typically composed of 56% of linoleic acid (18:2 n-6), 22% of oil vs.2μg/g for cold press oil). of α-linolenic acid (18:3 n-3), and 9% of oleic acid (18:1) The aim of this study was to evaluate SFE performance at (Callaway, 2004). Walnut oil can be classified in the same recovering residual oil when applied to five press cakes that ex- category with 56–65% of 18:2, 14–21% of 18:1, 9–15% of hibited different lipid contents and matrix characteristics. The 18:3 and 6–8% of palmitic acid (16:0) (Morin, 1996a). Poppy process efficiency was evaluated in terms of oil yield and oil seed oil is also a linoleic oil with 69–77% of 18:2, 13–18% characteristics. of 18:1, 9–11% of 16:0 and less than 3.5% of other fatty acids (Morin, 1996b). Linseed oil (also call flaxseed oil) is a linolenic oil and is typically composed of 59% of 18:3, 15% 2 Materials and methods of 18:2, 18% of 18:1 other fatty acids accounting for less than 10% of the total fatty acids (Przybylski, 2005). Sesame oil is an oleic-linoleic oil containing 39–47% of 18:2, 37–42% 2.1 Raw material of 18:1, 8–11% of 16:0 and 4–6% of stearic acid (18:0) (Morin, 1996b). These seeds present different fatty acid profiles but Press cakes were supplied by Bioplanète (Bram, France). have in common a high degree of unsaturation. Cakes came from organic seeds of poppy (Papaver som- Supercritical extraction has already been investigated for niferum L. var. nigrum), linseed (Linum usitatissimum L.), these five seeds and nut, and the studies generally focused hemp (Cannabis sativa L.) and sesame (Sesamum indicum). on the effect of process parameters (namely pressure, tem- Walnut (Juglans regia) cake was also used. The characteristics perature and flow rate) on extraction yield (on sesame (Corso of cakes are given in Table 1. et al., 2010;Dökeret al., 2010); on hemp (Da Porto et al., Total lipid content was determined by chloro- / 2012a, 2012b); on poppy (Bozan and Temelli, 2003); on wal- form methanol extraction according to Folch method (Folch, 1957). Water content was assessed using a thermobalance nut (Oliveira et al., 2002; Salgin and Salgin, 2006)). For ◦ instance, on linseed, SFE optimization (Bozan and Temelli, (Sartorius) at 105 C until mass variation became lower 2002;Ivanov,2012;Jiao,2008; Özkal, 2009; Rombaut, 2013) than 1 mg. Other characteristics were given by the supplier. showed that an increase of temperature and pressure increased the oil yield. Depending on extraction conditions, up to 82% of oil could be extracted with neat CO2. In Ivanov’s work (2012), 2.2 Supercritical fluid extraction ethanol was used as cosolvent, but it was directly added to the load prior to CO2 extraction. The higher the quantity of The scheme of the set-up is provided in Figure 1.The ethanol, the higher was the oil yield (up to 99%). Whilst SFE equipment is mainly composed of a 0.49 L cylindrical ves- is mainly investigated on raw seeds, SFE on press cake is more sel fed by two high pressure pumps (Gilson). Liquid CO2 (Air rarely reported. Dealing with walnut press cake, Martinez et al. Liquide, France) was first cooled to –0.3 ◦C before the pump (2008) recovered the oil with yield higher than 90% for SFE then heated to 45 ◦C by an electrical heater before being intro- ◦ carried out at 40 MPa and temperatures higher than 50 C. duced in the vessel. The vessel that contained the matrix was The oil quality is generally assessed by calorimetry, perox- thermally controlled by an electrical mantle.